Log Message:
Update to GNU Smalltalk 3.1.

There're numerous changes, which include various improvements,
new features and bug fixes.

Most notable changes include async. signal safety, threads support,
remote control of Smalltalk VM via TCP socket, DBI improvements,
bindings to Cairo, LibSDL, OpenGL and GLUT, Swazoo web server,
newer Seaside application server and web framework.